Since my husband wants to cut the nylon strap with the hot knife to seal the ends. (instead of using a lighter) I have been looking into the best stitch to sew the leashes.
I will be going with the Box X stitch. A heavy duty needle, and outdoor thread (if the old antique machine will handle it anyway) And the antique machine we have (even though I prefer my newer machine)
I found a video of the stitch I want to do, actually on the eBay page of another item from the same seller.
I will likely work on the leashes over the weekend so I can have my husband’s help even if it is just measuring the strap, cutting the strap and keeping the dog distracted.